From: Matt Corallo <git@bluematt.me>
Date: Mon, 15 Apr 2013 18:18:29 +0000 (-0400)
Subject: tweak, build.sh
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=421e5acbd6f375ca9f2f16d260fe9c5505fb42f4;p=shamirs

tweak, build.sh
---

diff --git a/build.sh b/build.sh
new file mode 100755
index 0000000..b473a52
--- /dev/null
+++ b/build.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+gcc shamirssecret.c -O2 -std=c99 -DTEST -o shamirssecret && ./shamirssecret &&
+gcc shamirssecret.c -O2 -std=c99 -o shamirssecret
diff --git a/shamirssecret.c b/shamirssecret.c
index cc3e713..be6eed3 100644
--- a/shamirssecret.c
+++ b/shamirssecret.c
@@ -102,6 +102,11 @@ static uint8_t field_pow_ret(uint8_t calc, uint8_t a, uint8_t e) {
 	return ret;
 }
 static uint8_t field_pow(uint8_t a, uint8_t e) {
+#ifndef TEST
+	// Although this function works for a==0, its not trivially obvious why,
+	// and since we never call with a==0, we just assert a != 0 (except when testing)
+	assert(a != 0);
+#endif
 	return field_pow_ret(exp[(log[a] * e) % 255], a, e);
 }